People should not be able to give money to politicians they are not eligible to vote for, i.e. rich people buying politicians on the other side of the country.
Companies, unions and trade associations are not people and should not be able to give money to politicians.
It is my understanding that the U.S. is definitely the outlier. Other countries like Canada, the U.K., Germany, Japan, etc don't allow money to influence politics like in the U.S.
More information: Our democracy no longer represents the people. Here's how we fix it | Larry Lessig | TEDxMidAtlantic | https://www.youtube.com/watch?v=PJy8vTu66tE